Renesas 71V321S25PFI8

Overview

71V321S25PFI8 from Renesas Electronics (formerly IDT) is a high-speed 3.3V 2K × 8 dual-port static RAM with on-chip interrupt logic and BUSY arbitration for interprocessor communication. It supports fully asynchronous access from left/right ports, delivers 25 ns max read cycle time, consumes 55 mA typical dynamic current, and operates across –40°C to +85°C industrial temperature range in a 64-pin TQFP package.

For engineers reviewing the 71V321S25PFI8 datasheet, 71V321S25PFI8 pinout, 71V321S25PFI8 application, or 71V321S25PFI8 equivalent, key selection criteria include dual-port arbitration timing (tBDD ≤ 30 ns), interrupt flag setup/reset (tINS/tINR ≤ 25 ns), 2V data retention capability (L version only), and compatibility with TTL-level 3.3V I/O interfaces in real-time embedded control systems.

Technical Context

The 71V321S25PFI8 implements independent left/right port control logic with separate CE, OE, R/W, address, and bidirectional I/O buses - enabling true concurrent read/write operations unless address contention triggers BUSY arbitration. Its totem-pole BUSY outputs (BUSYL/BUSYR) directly drive external stall logic without pull-ups, and internal arbitration prioritizes the earlier-arriving access based on tAPS ≥ 5 ns setup.

Interrupt functionality uses dedicated mailbox addresses (7FE_H for INTL, 7FF_H for INTR) with edge-triggered assertion via write cycles from the opposite port; flags are cleared by reading the same location. The device supports full standby (ISB3 ≤ 1.0 mA) and battery backup operation (2V V_CC, 100 µA max retention current), though 71V321S25PFI8 is the standard-power variant (not L-grade).

Key Specifications

Pinout & Package

71V321S25PFI8 is housed in a 64-pin TQFP (Thin Quad Flatpack), package code PNG64, body size 10 mm × 10 mm × 1.4 mm. All V_CC and GND pins must be connected per datasheet Note 1–2; unused pins (N/C) are not internally bonded.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-port SRAM applications.

Compared with CY7C024AV-25AXC and AS7C3256B-25JCIN, the 71V321S25PFI8 uniquely integrates both hardware BUSY arbitration and dual interrupt flags in a compact 2K × 8 footprint - reducing component count and eliminating timing-critical external logic for tightly coupled dual-processor systems.

Availability

71V321S25PFI8 is available at Aetrix Electronics and suitable for real-time motion control, dual-core industrial PLCs, avionics data concentrators, and medical imaging subsystems requiring stable component supply and long-term industrial temperature support.

Supply support for 71V321S25PFI8 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and memory solutions for automotive, industrial, infrastructure, and IoT applications.

The 71V321S25PFI8 belongs to Renesas' legacy dual-port SRAM product line, originally developed by IDT to enable deterministic interprocessor communication in hard real-time embedded systems without software overhead.

FAQ

What is the operating voltage range for the 71V321S25PFI8?

The 71V321S25PFI8 operates over a supply voltage range of 3.0 V to 3.6 V, with nominal 3.3 V operation. It is not 5V-tolerant, and all input levels must comply with VIH ≥ 2.0 V and VIL ≤ 0.8 V per the datasheet. This 3.3V-only specification ensures compatibility with modern low-voltage microcontrollers and FPGAs while maintaining signal integrity in noise-sensitive industrial environments. The 71V321S25PFI8 does not support battery backup operation - that feature is exclusive to the 'L' suffix variants.

Does the 71V321S25PFI8 support true simultaneous read/write operations?

Yes, the 71V321S25PFI8 supports fully asynchronous, independent read and write operations on left and right ports - provided no address contention occurs. When both ports access the same memory location concurrently, on-chip arbitration asserts BUSYL or BUSYR to stall the later-arriving access, ensuring data coherency. The 71V321S25PFI8 guarantees tAPS ≥ 5 ns setup time for priority resolution, and tBDD ≤ 30 ns for BUSY-to-valid-data recovery, making it suitable for deterministic dual-CPU architectures where timing predictability is critical.

How do the interrupt flags (INTL and INTR) function in the 71V321S25PFI8?

In the 71V321S25PFI8, INTL is asserted when the right port writes to address 7FE_H, and INTR is asserted when the left port writes to 7FF_H. These are level-sensitive flags cleared only by reading the respective address with appropriate CE/OE/RW settings - not by hardware reset. The 71V321S25PFI8 uses these fixed mailboxes to enable lock-free interprocessor signaling without polling, with tINS/tINR ≤ 25 ns guaranteeing fast flag response. No configuration registers or initialization sequence is required - interrupt behavior is hardwired per the datasheet truth tables.

What package type and pin count does the 71V321S25PFI8 use?

The 71V321S25PFI8 uses a 64-pin TQFP (Thin Quad Flatpack) package, designated PNG64, with dimensions 10 mm × 10 mm × 1.4 mm. It features four dedicated power/ground pairs (V_CC/GND), 22 address lines (11 per port), 16 bidirectional data lines (8 per port), and eight control/status signals (CEL/OEL/R/WL/CER/OER/R/WR/BUSYL/BUSYR/INTL/INTR). Pin 1 is located at the top-left corner adjacent to the index mark, and all V_CC pins must be decoupled locally per the 71V321S25PFI8 layout guidelines.

Is the 71V321S25PFI8 pin-compatible with other speed grades or power variants?

Yes, the 71V321S25PFI8 shares identical pinout and footprint with all members of the 71V321 family in the PNG64 (64-pin TQFP) package, including 71V321L25PFGI, 71V321S35PFGI, and 71V321L35PFGI. Electrical characteristics differ - notably ISB3 standby current (1.0 mA vs. 0.2 mA for L-grade) and ICC dynamic current (55 mA vs. 55 mA typ. but lower max for L) - but no PCB redesign is needed when substituting within the same package code. The 71V321S25PFI8 remains functionally identical across speed grades; only access timing parameters change.